EP0226592A1

EP0226592A1 - Liquid crystal phase.

Info

Publication number: EP0226592A1
Application number: EP86901864A
Authority: EP
Inventors: Bernhard Scheuble; Georg Weber
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 1985-03-25
Filing date: 1986-03-19
Publication date: 1987-07-01
Also published as: DE3665478D1; WO1986005799A1; EP0226592B1; DE3510733A1; KR870700087A; JPS62502409A

Abstract

Une phase cristalline liquide contient au moins un composant ayant la formule I: R1-A-Ph-R2, au moins un composant ayant la formule II: R3-Cy-Z1-Q-Z2-Phe-Ao-R4, au moins un composant choisi parmi les composés ayant les formules IIIa: R5-(Cy)m-Pyr-Phe-R6 et IIIb: R5-(Cy)m-A1-Pyr-R6 et/ou au moins un composant choisi parmi les composés ayant les formules IVa: R7-Dio-Phe-CN et IVb: R7-Ao-Phe-NCS. Cette phase cristalline liquide présente de bonnes qualités de multiplexage.A liquid crystalline phase contains at least one component having the formula I: R1-A-Ph-R2, at least one component having the formula II: R3-Cy-Z1-Q-Z2-Phe-Ao-R4, at least one component chosen from the compounds having the formulas IIIa: R5- (Cy) m-Pyr-Phe-R6 and IIIb: R5- (Cy) m-A1-Pyr-R6 and / or at least one component chosen from the compounds having the formulas IVa: R7-Dio-Phe-CN and IVb: R7-Ao-Phe-NCS. This liquid crystalline phase has good multiplexing qualities.

Description

Liquid crystal phase

The invention relates to liquid-crystalline phases (LC phases) with low viscosity, broad nematic phases and low temperature dependence of the threshold voltage.

It relates in particular to LC phases for use in LC display elements of the twisted nematic type which are suitable for multiplex operation or in SBE displays.

For liquid crystal display elements (LC display elements), the properties of nematic or nematic-cholesteric liquid-crystalline materials are increasingly being used to significantly change their optical properties such as light absorption, light scattering, birefringence, reflectivity or color under the influence of electrical fields. The function of such display elements is based, for example, on the phenomena of dynamic scattering, the deformation of aligned phases, the guest-host effect, the Schadt-Helfrich effect in the twisted cell, the SBE effect or the cholesteric-nematic phase transition.

For the technical application of these effects in electro-optical components, liquid-crystalline phases are required, which have to meet a variety of requirements. Chemical resistance to moisture, air and physical influences such as heat, radiation in the infrared, visible and ultraviolet range and electrical equal and alternating fields are particularly important here. Furthermore, from technical usable liquid-crystalline dielectrics required a liquid-crystalline mesophase in a suitable temperature range and the lowest possible viscosity at room temperature. After all, they must have no self-absorption in the visible light range, ie they must be colorless.

In none of the previously known series of compounds with liquid crystalline mesophase there is a single compound which meets all of these requirements. Mixtures of two to twenty, preferably three to fifteen, compounds are therefore generally prepared in order to obtain substances which can be used as liquid-crystalline phases. This usually involves mixing at least one compound with a low melting and clearing point. This usually gives a mixture whose melting point is below that of the lower melting component, while the clearing point lies between the clearing points of the components. However, it is not easy to establish optimal phases in this way because the components with the high

Melting and clearing points often also give the mixtures a high viscosity. As a result, the switching times of the electro-optical display elements produced in this way are undesirably extended.

The invention is based on the object of producing liquid-crystalline phases which have a nematic phase in the required temperature range, enable sufficiently short switching times in liquid-crystal cells at room temperature, have low temperature dependency of the threshold voltage and have extremely high chemical stability. A large number of liquid-crystalline phases based on a large number of compounds are already commercially available. However, there is still a great need for liquid crystalline phases with high clearing points, low melting points, low viscosity (and thus short switching times), low temperature dependence of the threshold voltage and high chemical stability, which are suitable for multiplex operation. The LC phases currently commercially available generally contain considerable amounts of ester compounds, for example of the formula

wherein R is n-alkyl or n-oxaalkyl and R 'n-alkyl, n-alkoxy, n-oxaalkyl or CN.

It has now been found that liquid crystal phases with particularly favorable combinations of material properties, in particular extraordinarily high chemical stability and particularly good multiplex properties, are obtained,

if they have at least one component of the formula I

R ¹ -A-Ph-R ²

in which R ^{1 is} alkyl having 1 to 12 C atoms, R ² alkyl, alkoxy or alkanoyloxy each having 1 to 12 C atoms,

A Cy or Dio,

Dio trans-1,3-dioxane-2,5-diyl,

Cy trans-1,4-cyclohexylene and

Ph means 1,4-phenylene, at least one component of formula II

R ³ -Cy-Z ¹ -QZ ² -Phe-A ° -R ⁴ II

in which R ³ and R ^{4 are} each alkyl having 1 to 12 carbon atoms,

Cy trans 1,4-cyclohexylene, Z ¹ and Z ² each independently

-CO-O-, -O-CO-, -CH ₂ CH ₂ - or a single bond, Q Phe or Cy,

A ° trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl or a single bond and

Phe in each case means 1,4-phenylene which is unsubstituted or substituted by a fluorine,

at least one component selected from the compounds of the formulas purple and illb

R ⁵ - (Cy) _m -Pyr-Phe-R ⁶ III

R ⁵ - (Cy) _m -A ¹ -Pyr-R ⁶ Illb

in which R ^{5 in} each case alkyl with 1 to 12 C atoms, R ⁶ alkyl, alkoxy or alkanoyloxy with in each case 1 to 12 C atoms, m 0 or 1,

Pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl and A ^{1 means} Phe or Cy and Cy and Phe have the meanings given, and / or at least one component selected from the compounds of the formulas IVa and IVb

R ⁷ -Dio-Phe-CN IVa

R ⁷ -A ° -Phe-NCS IVb in which R ⁷ each alkyl with 1 to 12 C atoms, A ° -Cy-, -Dio-, -Cy-Phe-, -Cy-Cy-, -Cy-Ph- CO-O- or -Cy-CH ₂ CH ₂ - means, and Dio and Phe have the meaning given.

The phases according to the invention preferably additionally comprise at least one component selected from the compounds of the formulas Va and Vb,

R ⁸ -Cy- (Phe) _n -CN Va

R ⁸ -Cy-Cy- (Phe) _n -CN Vb

wherein R ⁸ each represents alkyl having 1 to 12 carbon atoms, n represents 1 or 2 and Cy and Phe each have the meanings given.

and / or at least one component of the formula VI,

R ⁹ -Cy-A ¹ -ZA ² -R ¹⁰ VI

wherein R ^{9 is} alkyl having 1 to 12 carbon atoms, R ¹⁰ alkyl or alkoxy each having 1 to

12 carbon atoms or CN, A ¹ and A ² each Cy or Phe and

Z means -CO-O-, -O-CO- or -CH ₂ CH ₂ -. The invention thus relates to the liquid crystal phases described above, which may also contain two or more pleochroic dyes, and the use of these phases in liquid crystal display elements.

The invention furthermore relates to liquid crystal display elements which contain such phases.

In principle, all pleochroic dyes suitable for guest-host mixtures can be used as dyes. The most important of these dyes belong to the classes of antrachinone, naphthoquinone, azo, indigo and / or perylene dyes.

These are described in rich diversity in the literature. The person skilled in the art can easily select the dyes which are most suitable for the particular application. For example, Anthraquinone dyes described in EP 34 832, EP 44 893, EP 48 583, EP 54 217, EP 56 492, EP 59 036, GB 20 65 158, GB 20 65 695, GB 20 81 736, GB 20 82 196, GB 20 94 822, GB 20 94 825, JP-OS 55-123673,

JP-OS 56-112 967, JP-OS 57 165 456, JP-OS 59-020 355, DE 30 17 877, DE 30 40 102, DE 30 48 552, DE 31 00 533, DE 31 15 147, DE 31 15 762, DE 31 50 803, DE 32 01 120 and DE 33 09 045, naphthoquinone dyes described in DE 31 26 108 and 32 02 761, azo dyes in

EP 43 904, DE 31 23 519, DE 32 45 751, DE 33 09 048, PCT WO 82/2054, GB 20 79 770, JP-OS 56-57 850, JP-OS 56-104 984, JP-PS 55 -052 375, JP-OS 59-096 171, JP-OS 59-093 776, US 4,308,161, US 4,308,162, US 4,340,937, T. Uchida, C. Shishido, H. Seki and M. Wada: Mol. Cryst. Lig. Cryst. 39, 39-52 (1977) and H. Seki, C. Shishido, S. Yasui and T. Uchida: Jpn. J. Appl. Phys. 21, 191-192 (1982) and perylenes described in EP 60 895, EP 68 427 and PCT WO 82/1191.

By suitable choice of the dye components and the relative dye concentrations, the guest-host systems according to the invention can be adapted to a wide variety of applications.

The individual compounds of the formulas I-VI of the liquid-crystal phases according to the invention are either known or their preparation methods can be readily derived from the prior art for the person skilled in the art, since they are based on standard processes described in the literature.

In the above formulas, alkoxy or alkanoyloxy means -O-alkyl or -O-CO-alkyl. In all formulas, alkyl means a straight-chain alkyl group, in which one non-terminal or two non-adjacent and non-terminal CH ₂ groups could also be replaced by -O- or -CH = CH-.

Alkyl preferably means methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-alkoxymethyl or n-alkoxyethyl, preferably in each case 2 to 7 carbon atoms or trans-alkenyl with 3 to 7 carbon atoms.

If the alkyl groups of the components of the formulas I to VI contain 3 or more carbon atoms, these can be arranged in a straight or branched chain. However, no components are used in the phases according to the invention which contain more than one branched alkyl group. Such branched alkyl groups do not contain in the context of the present invention more than one chain branch; it is preferably a methyl or ethylene group in the 1- or 2-position of the carbon skeleton, so that the following are particularly suitable as branched alkyl groups: 2-methylpropyl, 2-methylbutyl, 1-methylpentyl, 2-methylpentyl, 1-methylhexyl . As a rule, the liquid-crystalline dielectrics according to the invention contain only one component with a branched-chain alkyl radical in order to induce optical activity if desired. For this purpose, normally no more than 10% by weight, preferably 0.5 to 3% by weight, of a component with a branched alkyl radical is added. Otherwise, compounds of the formula I to IV in which the alkyl radicals are straight-chain, ie methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, are preferably used as components of the phase according to the invention. n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl.

A is preferably Cy. Z ¹ and Z ² in formula II preferably each represent a single bond. Preference is furthermore given to compounds of the formula II in which one of the groups Z ¹ and Z ² denotes -CH ₂ CH ₂ - and the other

Group -CH ₂ -CH ₂ -, -CO-O- or -O-CO-. Q is preferably Phe.

The LC phases according to the invention preferably contain

5 to 38, in particular 8 to 23% of one or more components of the formula I. Particularly preferred are LC phases according to the invention containing 10 to 22% of one or more components of the formula I. R is preferably n-alkyl or n- (trans ) Alkenyl with 2 to 7, in particular with 3 to 5, carbon atoms or an oxaalkyl group with 2 to 6 carbon atoms. R ² is preferably n-alkyl or n-alkoxy, each having 1 to 5 carbon atoms. Preferably The LC phases according to the invention contain at least one compound of the formula I in which R ^{2 is} n-alkoxy.

The LC phases according to the invention preferably contain 5 to 45, in particular 5-35% of one or more components of the formula II. Particular preference is given to

LC phases containing 12 to 27% of one or more components of the formula II. R ³ and R ⁴ are each preferably independently of one another n-alkyl or n-oxaalkyl each having 2 to 7, in particular 3 to 5, carbon atoms. The LC phases preferably contain at least one compound of the formula I in which A ° is trans-1,4-cyclohexylene and / or one group Phe is 2-fluoro-1,4-phenylene and the other group is Phe 1,4-phenylene .

Formula II preferably comprises compounds of the partial form in IIa to m:

R ³ -Cy-Ph-Ph-R ⁴ IIa

R ³ -Cy-Cy-Phe-R ⁴ Ilb R ³ -Cy-Ph-Ph-Cy-R ⁴ IIc

R ³ -Cy-Phe-Ph-R ⁴ Ild

R ³ -Cy-Phe-Ph-Cy-R ⁴ IIe

R ³ -Cy-CH ₂ CH ₂ -Phe-Phe-R ⁴ Ilf

R ³ -Cy-CH ₂ CH ₂ -Phe-Phe-CH ₂ CH ₂ -Cy-R ⁴ IIg R ³ -Cy-CH ₂ CH ₂ -Phe-Phe-Cy-R ⁴ Ilh

R ³ -Cy-COO-Ph-Ph-R ⁴ Ili

R ³ -Cy-CH ₂ CH ₂ -Phe-CH ₂ CH ₂ -Phe-Cy-R ⁴ IIj

R ³ -Cy-CH ₂ CH ₂ -Cy-Phe-R ⁴ Ilk

R ³ -Cy-CH ₂ CH ₂ -Cy-Phe-Cy-R ⁴ III R ³ -Cy-Phe-COO-Phe-Cy-R ⁴ IIm The LC phases according to the invention preferably contain both at least one compound of the formula II in which A ° denotes a single bond and at least one compound of the formula II in which A ° denotes trans-1,4-cyclohexylene.

The LC phases according to the invention preferably contain

10 to 45, in particular 20-35%, on one or more

Components of formula III. Are particularly preferred

LC phases containing 21 to 33% of one or more components of the formula III. m is preferably 0. R ⁵ is preferably n-alkyl having 3 to 12, in particular 6 to 9, carbon atoms. R ⁶ is preferably n-alkoxy or n-alkyl having 1 to 12 carbon atoms. FK phases preferably contain at least three, in particular at least five, compounds of the formula III.

Formula III a preferably comprises compounds of the sub-formulas Illaa and Illab,

R ⁵ -Pyr-Phe-R ⁶ Illaa

R ⁵ -Cy-Pyr-Phe-R ⁶ IIIab

of which the compounds of the formula Illaa are particularly preferred. Pyr is preferably pyrimidine-2,5-diyl. R ⁵ is preferably straight-chain alkyl having 3 to 9 carbon atoms. R ⁵ is preferably straight-chain alkyl or alkoxy having 2 to 9 carbon atoms. Formula Illb includes preferred compounds of the subforms in Illba, Illbb and Illbc,

R ⁵ -Cy-Pyr-R ⁶ Illba

R ⁵ -Cy-Phe-Pyr-R ⁶ Illbb

R ⁵ -Cy-Cy-Pyr-R ⁶ Illbc of which the compounds of the formulas Illbb and Illbc are particularly preferred. R ⁵ and R ⁶ each preferably represent alkyl having 2 to 9 carbon atoms.

The LC phases according to the invention preferably contain 5 to 45, in particular 14 to 38%, of one or more components of the formula IV. Particularly preferred

LC phases containing 21 to 33% of one or more components of the formula IV. R ⁷ is preferably n-alkyl having 2 to 7, in particular 2 to 5, carbon atoms.

Formula IVb includes compounds of the sub-formulas IVba to IVbf

R ⁷ -Cy-Phe-NCS IVba

R ⁷ -Dio-Phe-NCS IVbb R ⁷ -Cy-Phe-Phe-NCS IVbc R ⁷ -Cy-Cy-Phe-NCS IVbd

R ⁷ -Cy-CH ₂ CH ₂ -Phe-NCS IVbe

R ⁷ -Cy-Ph-COO-Phe-NCS IVbf, of which compounds of the formulas IVba, IVbc, IVbd and IVbe are particularly preferred. R ⁷ is preferably straight-chain alkyl, alkoxy or (trans) alkenyl with preferably 2 to 7 carbon atoms. Phe is preferably 1,4-phenylene.

Phases according to the invention which simultaneously contain compounds of the formulas I, II, III (a and / or b) and IV (a and / or b) are preferred. These phases preferably contain compounds of the formula IVa. Preference is furthermore given to phases which simultaneously contain compounds of the formulas I, II and IVb, these phases preferably containing trinuclear and tetranuclear compounds of the formula II (ie A ° is a single bond in one or more compounds of the formula II and one or more Compounds of the formula II Cy or Dio, preferably Cy. The proportions by weight of the components of the formulas I to IV in the LC phases according to the invention are preferably in the ranges given below.

I II = 0.63-1.53

I II = 0.67-0.82

I IV = 0.71-1.64

II II = 0.45 - 1.25

II IV = 0.48 - 2.50

III IV = 0.90-2.35

Also preferred are LC phases according to the invention containing at least one component of the formula Va and / or Vb, in which R ⁸ preferably denotes n-alkyl having 2 to 7 C atoms and Phe 1,4-phenylene or 3-fluoro-1,4- Is phenylene.

The proportion of this compound (s) is preferably in the range from 4 to 15%. Compounds of formula Va are preferred.

Also preferred are LC phases according to the invention containing at least one component of the formula VI, in which R ^{9 is} preferably n-alkyl or n-oxaalkyl having 2 to

5 carbon atoms, R ^{10 is} preferably n-alkyl, n-alkoxy or n-oxaalkyl each having 2 to 7 carbon atoms or CN. A ¹ is preferably trans-1,4-cyclohexylene or 1,4-phenylene. A ² is preferably trans-1,4-cyclohexylene or 3-fluoro-1,4-phenylene. Z is preferably -CO-O- or -CH ₂ CH ₂ -. The proportion of these compounds is preferably 3 to 15%. The phases according to the invention are produced in a conventional manner. As a rule, the desired amount of the components used in smaller amounts is dissolved in the components which make up the main constituent, advantageously at elevated temperature. If a temperature above the clearing point of the main constituent is chosen, the completeness of the dissolving process can be observed particularly easily.

However, it is also possible to use solutions of the components in a suitable organic solvent

Example, mix acetone, chloroform or methanol and remove the solvent after thorough mixing, for example by distillation under reduced pressure. Of course, with this procedure, care must be taken to ensure that no impurities or undesirable dopants are introduced by the solvent.

By means of suitable additives, the liquid-crystalline phases according to the invention can be modified so that they can be used in all types of liquid-crystal display elements which have hitherto become known.

Such additives are known to the person skilled in the art and are described in detail in the literature. For example, conductive salts, preferably ethyl-dimethyl-dodecylammonium-4-hexylocybenzoate, tetrabutylammonium-tetraphenylboranate or complex salts of crown ethers (see, for example, I. Haller et al., Mol. Cryst. Lig. Cryst. Volume 24, pages 249-258, ( 1973)) to improve the conductivity or substances to change the dielectric anisotropy, pie, the viscosity and / or the orientation of the nematic phases are added. Such substances are described, for example, in DE-OS 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430, 28 53 728 and 29 02 177.

The following examples are intended to illustrate the inventions without limiting them. In the examples, the melting point and clearing point of a liquid-crystalline substance are given in degrees Celsius. The percentages relate to percentages by weight.

example 1

A liquid crystalline phase

6% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

14% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

11% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% p-trans-4-ethylcyclohexyl-benzoic acid (p-cyanophenyl ester)

7% p-trans-4-pentylcyclohexylbenzoic acid (p-cyanophenyl ester) 2% p- (p-pentylbenzoyloxy) benzoic acid (pcyanophenyl ester), 18% butyric acid (p-trans-4-propylcyclohexylphenyl ester), 5 % trans-1-p-methoxyphenyl-4-propylcyclohexane, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 7% 2-p-pentyloxyphenyl-5-hexylpyrimidine, 7% 2- p-hexyloxyphenyl-5-hexylpyrimidine, 7% 2-p-heptyloxyphenyl-5-hexylpyrimidine and 7% 2-p-nonyloxyphenyl-5-hexylpyrimidine

has a clearing point of 65.5 °, a dielectric anisotropy of +10.6, an optical anisotropy of 0.129, a threshold voltage V _10.0.20 = 1.5 volts and a K ₃ / K ₁ of 0.92. Example 2

A liquid crystalline phase

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

6% 2-p-pentyloxyphenyl-5-hexylpyrimidine,

6% 2-p-hexyloxyphenyl-5-hexylpyrimidine,

6% 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5% 2-p-nonyloxylphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxylphenyl-5-heptylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine,

4% trans-4-pentylcyclohexane carboxylic acid (p-trans-4-propylcyclohexylphenyl ester), 10% trans-1-p-methoxyphenyl-4-propylcyclohexane and

11% trans-1-p-propylphenyl-4-pentylcyclohexane

has a melting point of -14 °, a clearing point of 68.2 °, a dielectric anisotropy of +7.4, an optical anisotropy of 0.125, a threshold voltage V _10.0.20 of 2.1 volts and K _{3 /} K ₁ of 0.81.

Example 3

A liquid crystalline phase

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane, 7% 2-p-cyanophenyl-5-propyl-1,3-dioxane, 8% 2-p-cyanophenyl-5-butyl-1, 3-dioxane, 7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl,

5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

6% 2-p-pentyloxyphenyl-5-hexylpyrimidine,

6% 2-p-hexyloxyphenyl-5-hexyipyrimidine,

6% 2-p-heptyloxyphenyl-5-hexylipyrimidine,

5% 2-p-nonyloxylphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyIphenyl-5-heptyIpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine,

3% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl,

8% trans-1-p-methoxyphenyl-4-propylcyclohexane and 5% trans-1-p-propylphenyl-4-pentylcyclohexane

has a melting point of -14 °, no smectic / nematic phase transition to -40 °, a clearing point of 64.4 °, a dielectric anisotropy of +7.1, an optical anisotropy of 0.1248, a threshold voltage V _{10.0, 20} of 2.0 volts and a K ₃ / K ₁ of 0.80.

Example 4

A liquid crystalline phase

7% 2-p-cyanophenyl-5-ethyl-1,3-dioxane, 11% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

11% 2-p-cyanophenyl-5-butyl-1,3-dioxane, 9% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

12% p-trans-4-propylcyclohexyl-benzonitrile,

6% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl, 6% 4- (trans-4-pentylcyclohexyl) -4 '- {trans-4-propylcyclohexyl) biphenyl,

8% trans-1-p-methoxyphenyl-4-propylcyclohexane, 4% 2-p-methoxyphenyl-5-heptylpyrimidine,

6% 2-p-nonyloxyphenyl-5-heptylpyrimidine,

4% 2-p-methoxyphenyl-5-nonylpyrimidine,

8% 2-p-hexyloxyphenyl-5-nonylpyrimidine and 8% 2-p-nonyloxyphenyl-5-nonylpyrimidine

has a clearing point of 62 °, an optical anisotropy of 0.129 and a threshold voltage V _10.0.20 of 1.6 volts.

Example 5

A liquid crystalline phase

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane, 10% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

5% 2-p-pentoxyphenyl-5-hexylpyrimidine,

5% 2-p-hexoxyphenyl-5-hexylpyrimidine,

5% 2-p-heptoxyphenyl-5-hexyipyrimidine,

5% 2-p-nonoxyphenyl-5-hexylpyrimidine, 5% 2-p-heptoxyphenyl-5-heptylpyrimidine,

5% 2-p-nonoxyphenyl-5-heptylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

5% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl, 8% trans-1-p-methoxyphenyl-4-propylcyclohexane and

14% trans-1-p-propylphenyl-4-pentylcyclohexane

has a melting point of -12 °, a clearing point of 65 °, a dielectric anisotropy of +7.0, an optical anisotropy of 0.1249, a threshold voltage V _10.0.20 of 2.0 volts and in the K ₃ / K ₁ in 0.77. Example 6

A liquid crystalline phase

8% p-trans-4-propylcyclohexyl-benzonitrile,

7% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

12% trans-1-p-methoxyphenyl-4-propylcyclohexane,

11% trans-1-p-butoxyphenyl-4-propylcyclohexane,

12% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

7% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl,

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4' - (trans-4-propylcyclohexyl) -2- fluorobiphenyl, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

4% 2-p-methoxyphenyl-5-hexylpyrimidine, 4% 2-p-methoxyphenyl-5-heptylpyrimidine, 4% 2-p-heptoxyphenyl-5-heptylpyrimidine, 4% 2-p-nonoxyphenyl-5-heptylpyrimidine and 4% 2-p-methoxyphenyl-5-nonylpyrimidine

has a melting point of -18 °, a clearing point of 85 °, a dielectric anisotropy of +5.7, an optical anisotropy of 0.1358, a threshold voltage V _10.0.20 of 2.5 volts and a K ₃ / K ₁ of 0.94.

Example 7

A liquid crystalline phase consisting of

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane, 7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

13% trans-1-p-methoxyphenyl-4-propylcyclohexane,

10% trans-1-p-butoxyphenyl-4-propylcyclohexane,

2% 4-nonyl-4 '- (trans-4-butylcyclohexyl) biphenyl, 11% 4-ethyl-4' - (trans-4-pentylcyclohexyl) biphenyl,

2% 4-nonyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl,

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl,

4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl,

5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

4% 2-p-methoxyphenyl-5-hexylpyrimidine,

4% 2-p-methoxyphenyl-5-heptylpyrimidine,

5% 2-p-heptoxyphenyl-5-heptylpyrimidine,

3% 2-p-nonoxyphenyl-5-heptylpyrimidine and 4% 2-p-methoxyphenyl-5-nonylpyrimidine

has a melting point of -19 °, a clearing point of 90 °, an optical anisotropy of 0.1348, a threshold voltage V _10.0.20 of 2.5 volts and a K ₃ / K ₁ of 0.92.

Example 8

A liquid crystalline phase consisting of

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane, 7% a 2-p-cyanophenyl-5-pentyl-1,3-dioxane, 5% p- (5-hexylpyrimidinyl) phenyl-p pentylbenzyl ether, 10% p- (5-heptylpyrimidinyl) phenyl-p-pentyl benzyl ether,

8% p- (5-heptylpyrimidinyl) phenyl-p-hexylbenzyl ether,

5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

10% trans-1-p-methoxyphenyl-4-propylcyclohexane, 5% 2-p-methoxyphenyl-5-hexylpyrimidine, 5% 2-p-pentoxyphenyl-5-hexylpyrimidine, 5% 2-p-heptoxyphenyl-5-hexylpyrimidine, 5% 2-p-methoxyphenyl-5-heptylpyrimidine, 5% 2-p-heptoxyphenyl-5-heptylpyrimidine and 5% 2-p-nonoxyphenyl-5-heptylpyrimidine

has a melting point of -14 °, a clearing point of 70 °, a dielectric anisotropy of +8.0, an optical anisotropy of 0.149, a threshold voltage V _10.0.20 of 2.0 volts and a K ₃ / K ₁ of 0.77.

Example 9

A liquid crystalline phase consisting of

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane, 7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane, 4% 4-nonyl-4 '- (trans-4- pentylcyclohexyl) biphenyl,

11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl, 5% 2-p-heptoxyphenyl-5-hexylpyrimidine,

5% 2-p-nonoxyphenyl-5-hexylpyrimidine,

5% 2-p-heptoxyphenyl-5-heptylpyrimidine, 5% 2-p-nonoxyphenyl-5-heptylpyrimidine,

5% 2-p-hexoxyphenyl-5-nonylpyrimidine, 5% 2-p-nonoxyphenyl-5-nonylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

6% trans-1-p-methoxyphenyl-4-propylcyclohexane and 16% trans-1-p-propylphenyl-4-pentylcyclohexane

has a melting point of -14 °, a clearing point of 61 °, a dielectric anisotropy of +6.8, an optical anisotropy of 0.1219, a threshold voltage V _10.0.20 of 2.0 volts and a K ₃ / K ₁ in 0.75.

Example 10

A liquid crystalline phase consisting of

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

7% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

5% 2-p-pentoxyphenyl-5-hexylpyrimidine,

5% 2-p-hexoxyphenyl-5-hexylpyrimidine, 5% 2-p-heptoxyphenyl-5-hexylpyrimidine,

5% 2-p-heptoxyphenyl-5-heptylpyrimidine, 4% 2-p-nonoxyphenyl-5-heptylpyrimidine,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans¬

4-propylcyclohexyl) biphenyl, 4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl, 6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 4% 4 , 4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl,

8% trans-1-p-methoxyphenyl-4-propylcyclohexane and 14% trans-1-p-propylphenyl-4-pentylcyclohexane has a melting point of -17 °, a clearing point of 78 °, a dielectric anisotropy of +7.0, an optical anisotropy of 0.1222, a threshold voltage V _10.0.20 of 2.1 volts and a K ₃ / K ₁ of 0.84.

Example 11

A liquid-crystalline phase is produced, consisting of

5% p-trans-4- (2-oxapropyl) cyclohexylbenzonitrile,

3% p-trans-4- (3-oxabutyl) cyclohexylbenzonitrile, 7% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

12% trans-1-p-methoxyphenyl-4-propylcyclohexane,

11% trans-1-p-butoxyphenyl-4-propylcyclohexane,

12% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl, 7% 4-ethyl-4' - (trans-4-propylcyclohexyl) biphenyl,

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4' - (trans-4-propylcyclohexyl) -2- fluorobiphenyl, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 4% 2-p-methoxyphenyl-5-hexylpyrimidine, 4% 2-p-methoxyphenyl-5-heptylpyrimidine, 4% 2 -p-heptoxyphenyl-5-heptylpyrimidine, 4% 2-p-nonoxyphenyl-5-heptyipyrimidine and 4% 2-p-ethylphenyl-5-nonylpyrimidine. Example 12

A liquid-crystalline phase consisting of

6% 2-p-cyanophenyl-5-propyl-1,3-dioxane, 14% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

11% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% p-trans-4-ethylene-cyclohexyl-benzoic acid (p-cyanophenyl ester)

7% p-trans-4-pentylcyclohexyl-benzoic acid (4-cyan-3-fluorophenyl ester),

2% p- (p-pentylbenzoyloxy) benzoic acid (p-cyanophenyl ester), 18% butyric acid (p-trans-4-propylcyclohexyl phenyl ester), 5% trans-1-p-methoxyphenyl-4-propylcyclohexane, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 7% 2-pentyloxyphenyl-5-hexylpyrimidine, 7% 2-hexyloxyphenyl-5-hexylpyrimidine, 7% 2-heptyloxyphenyl-5-hexylpyrimidine and

7% 2-nonyloxyphenyl-5-hexylpyrimidine.

Example 13

A liquid crystalline phase consisting of

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane, 7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-isothiocyanatophenyl-5-butyl-1,3-dioxane, 7% 2-p-isothiocyanatophenyl-5-pentyl-1,3-dioxane,

10% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl 5% 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5% 2-p-hexyloxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5% 2-p-nonyloxyphenyl-5-heptylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 8% 2-p-methoxyphenyl-5-propyl-1,3-dioxane and 14% trans-1-p-propylphenyl-4-pentylcyclohexane

has a clearing point of 64 °, a viscosity of 37 mm ² / s at 20 ° and K ₃ / K ₁ (20 °) of 0.73.

Example 14

A liquid crystalline phase consisting of

5% trans-1-p-isothiocyanatophenyl-4-ethylcyclohexane,

7% trans-1-p-isothiocyanatophenyl-4-propylcyclohexane, 8% 2-p-isothiocysnatophenyl-5-butyl-1,3-dioxane,

7% 2-p-isothiocyanatophenyl-5-pentyl-1,3-dioxane, 10% 4-ethyl-4 '- (tians-4-propylcyclohexyl) biphenyl, 5% 2-p-pentyloxyphsnyl-5-hexylpyrimidine,

5% 2-p-hexyloxyphenyl-5-hexylpyrimidine, 5% 2-p-heptyloxyphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine,

5% 2-p-nonyloxyphenyl-5-heptylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 8% 2-p-methoxyphenyl-5-propyl-1,3-dioxane and 14% trans-1 -p-propylphenyl-4-pentylcyclohexane

has a clearing point of 66 °, and viscosity of 32 mm ² / s at 20 ° and K ₃ / K ₁ (20 °) of 0.76.

Example 15

A liquid crystalline phase consisting of

9% 2-p-isothiocyanatophenyl-5-pentyl-1,3-dioxane, 7% 2-p-isothiocyanatophenyl-5-heptyl-1,3-dioxane,

8% 2-p-cyanophenyl-5-butyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl, 4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl,

5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

6% 2-p-pentyloxyphenyl-5-hexylpyrimidine,

6% 2-p-hexyloxyphenyl-5-hexylpyrimidine, 6% 2-p-heptyloxyphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine,

5% 2-p-nonyloxyphenyl-5-heptylpyrimidine,

10% 2-p-ethoxyphenyl-5-pentyl-1,3-dioxane and 11% trans-1-p-propylhexyl-4-pentylcyclohexane

has a clearing point of 66 °, a viscosity of 40 mm ² / s at 20 ° and K ₃ / K ₁ (20 °) of 0.82. Example 16

A liquid crystalline phase consisting of

9% trans-1-p-isothiocyanatophenyl-4-pentylcyclohexane, 7% trans-1-p-isothiocyanatophenyl-4-heptylcyclohexane,

8% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-pentyl-1,3-dioxane,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl,

5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl,

6% 2-p-pentyloxyphenyl-5-hexylpyrimidine, 6% 2-p-hexyloxyphenyl-5-hexylipyrimidine,

6% 2-p-heptyloxyphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylpyrimidine,

5% 2-p-nonyloxyphenyl-5-heptylpyrimidine, 10% 2-p-methoxyphenyl-5-pentyl-1,3-dioxane and

11% trans-1-p-propylphenyl-4-pentylcyclohexane

has a clearing point of 67 °, a viscosity of 38 mm ² / s at 20 ° and K ₃ / K ₁ (20 °) of 0.83.

Example 17

A liquid crystalline phase consisting of

15% p-trans-4-propylcyclohexylbenzonitrile,

9% trans-1-p-isothiocyanatophenyl-4-propylcyclohexane, 5% 4-ethyl-4'-cyanbiphenyl, 4% 4-propyl-4'-cyanbiphenyl,

4% 4-butyl-4'-cyanbiphenyl,

15% trans-1-p-ethoxyphenyl-4-propylcyclohexane,

9% trans-1-p-butoxyphenyl-4-propylcyclohexane,

9% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl, 7% 4-ethyl-4' - (trans-4-pentylcyclohexyl) biphenyl,

4% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl,

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 4% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl, 5% 4, 4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl and

5% 4,4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl

shows no smectic phase down to -40 °, a clearing point of 101 °, a viscosity of 21 mm ² / s at 20 °, a Δε of +7.3 and an optical anisotropy Δn of 0.154.

Example 18

A liquid crystalline phase consisting of

16% trans-1-p-isothiocyanatophenyl-4-propylcyclohexane, 4% trans-1-p-cyanophenyl-4-pentylcyclohexane,

18% trans-1-p-ethylphenyl-4-propylcyclohexane,

20% trans-1-p-methoxylphenyl-4-propylcyclohexane,

11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl,

11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl, 4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl, 3% 4,4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl,

3% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and

4% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl

shows no smectic phase down to -40 °, below the clearing point of 83 °, a viscosity of 14 mm ² / s at 20 °, a dielectric anisotropy Δε of +2.7 and an optical anisotropy Δn of 0.132.

Example 19

A liquid-crystalline phase is produced consisting of

16% trans-1-p-isothiocyanatophenyl-4-propylcyclohexane, 4% trans-trans-4-p-cyanphenyl-4'-pentylcyclohexylcyclohexane, 18% trans-1-p-ethylphenyl-4-propylcyclohexane,

20 / o trans-1-p-methoxylphenyl-4-propylcyclohexane,

11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl,

11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl, 3% 4,4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 3% trans, trans-4-p- Propylhexyl-4'-pentylcyclohexylcyclohexane 6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and 4% 4- (trans-4-pentylcyclohexyl) -4' - (trans-4-propylcyclohexyl) -2- fluorobiphenyl.

Example 20

A liquid-crystalline phase is produced consisting of

16% trans-1-p-isothiocyanatophenyl-4-propylcyclohexane, 4% trans-1-p-cyanphenyl-4-pentylcyclohexane, 18% trans-1-p-ethylphenyl-4-propylcyclohexane, 20% trans-1-p- Methoxylphenyl-4-propylcyclohexane, 11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl, 11% 4-ethyl-4' - (trans-4-pentylcyclohexyl) biphenyl, 4% 4.4 ' - bis (trans-4-propylcyclohexyl) biphenyl, 3% 4,4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl,

3% trans-trans-4- (trans-4-pentylcyclohexylethyl) - 4'-propylcyclohexylcyclohexane 6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and

4% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-f luorbiphenyl.

Example 21

A liquid-crystalline phase is produced consisting of

5% 2-p-cyanophenyl-5-ethyl-1,3-dioxane,

7% 2-p-cyanophenyl-5-propyl-1,3-dioxane,

8% 2-p-isothiocyantophenyl-5-butyl-1,3-dioxane, 7% 2-p-isothiocyantophenyl-5-pentyl-1,3-dioxane,

10% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl

5% 2-p-pentyloxyphenyl-5-hexylpyrimidine,

5% 2-p-hexylphenyl-5-hexylpyrimidine,

5% 2-p-heptylphenyl-5-hexylpyrimidine,

5% 2-p-nonoxyphenyl-5-hexylpyrimidine,

5% 2-p-heptyloxyphenyl-5-heptylipyrimidine,

5% 2-p-nonyloxyphenyl-5-heptylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 8% 2-p-methoxyphenyl-5-propyl-1,3-dioxane and 14% trans-1-p-propylphenyl-4-pentylcyclohexane.

Example 22

A liquid-crystalline phase is produced consisting of

8% 2-p-isothiocyantophenyl-5-butyl-1,3-dioxane,

7% 2-p-isothiocyantophenyl-5-pentyl-1,3-dioxane,

10% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl 5% 2-p-pentyloxyphenyl-5-hexylpyrimidine,

5% 2-p-hexyloxyphenyl-5-hexyipyrimidine,

5% 2-p-heptyloxyphenyl-5-hexylpyrimidine,

5% 2-p-nonyloxyphenyl-5-hexylpyrimidine,

5% 2-p- (trans-4-pentylcyclohexyl) phenyl-5-hexylpyrimidine, 5% 2- (trans, trans-4-propylcyclohexylcyclohex-4'-yl) -5-hexylpyrimidine,

6% 4,4'-bis (trans-4-pentylcyclohexyl) -2-fluorobiphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 8% 2-p-methoxyphenyl-5-propyl-1,3-dioxane and 4% trans-1-p-propylphenyl-4-pentylcyclohexane.

Example 23

A liquid crystalline phase consisting of

16% p-trans-4-propylcyclohexylbenzonitrile,

5% p-trans-4-pentylcyclohexylbenzonitrile,

4% 4-isothiocyanato-4 '- (trans-4-oentylcyclohexyl) biphenyl, 18% trans-1-p-ethylphenyl-4-propylcyclohexane,

20% trans-1-p-methoxyphenyl-4-propylcyclohexane,

11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl,

11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-proylcyclohexyl) -2-fluorobiphenyl

shows a clear point of 30 ° and a viscosity of 15 mm ² / s at 20 °. Example 24

A liquid crystalline phase consisting of

16% p-trans-4-propylcyclohexylbenzonitrile,

5% p-trans-4-pentylcyclohexylbenzonitrile, 4% trans, trans-4 '- (p-isothiocyanatophenyl) -4-propylcyclohexylcyclohexane,

18% trans-1-p-ethylphenyl-4-propylcyclohexane,

20% trans-1-p-methoxyphenyl-4-propylcyclohexane,

11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl, 11% 4-ethyl-4' - (trans-4-pentylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl

shows a clearing point of 80 "and a viscosity of 14 mm ² / s at 20 °.

Example 25

A liquid-crystalline phase is produced consisting of

16% p-trans-4-propylcyclohexylbenzonitrile,

5% p-trans-4-pentylcyclohexylbenzonitrile,

4% 1 - (p-isothiocyanatophenyl) -2- (trans-4-propylcyclohexyl) -ethane, 18% trans-1-p-ethylphenyl-4-propylcyclohexane,

20% trans-1-p-methoxyphenyl-4-propylcyclohexane, 11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl. 11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and 5% 4- (trans-4-pentylcyclohexyl) -4' - (trans-4-propylcyclohexyl) -2- fluorobiphenyl.

Example 26

A liquid-crystalline phase is produced consisting of

16% p-trans-4-propylcyclohexylbenzonitrile,

5% p-trans-4-pentylcyclohexylbenzonitrile,

4% p- (trans-4-propylcyclohexyl) benzoic acid (p-isothiocyanatophenyl ester),

18% trans-1-p-ethylphenyl-4-propylcyclohexane, 20% trans-1-p-methoxyphenyl-4-propylcyclohexane,

11% 4-ethyl-4 '- (trans-4-propylcyclohexyl) biphenyl,

11% 4-ethyl-4 '- (trans-4-pentylcyclohexyl) biphenyl,

4% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl,

6% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) biphenyl and

5% 4- (trans-4-pentylcyclohexyl) -4 '- (trans-4-propylcyclohexyl) -2-fluorobiphenyl.

Claims

Liquid crystal phase

1. Liquid crystal phase, characterized in that it contains at least one component of the formula I.

R ¹ -A-Ph-R ² I

A Cy or Dio,

Dio trans-1,3-dioxane-2,5-diyl,

Cy trans-1,4-cyclohexylene and

Ph means 1,4-phenylene,

at least one component of formula II

R ³ -Cy-Z ¹ -QZ ² -Phe-A ° -R ⁴ II

in which R ³ and R ^{4 are} each alkyl having 1 to 12 carbon atoms,

Cy trans 1,4-cyclohexylene, Z ¹ and Z ² each independently

-CO-O-, -O-CO-, -CH ₂ CH ₂ - or one

Single bond,

Q Phe or Cy,

A ° trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl or a single bond and

Phe in each case means unsubstituted or fluorine-substituted 1,4-phenylene, at least one component selected from the compounds of the formulas IIa and IIIb

R ⁵ - (Cy) _m -Pyr-Phe-R ⁶ III

R ⁵ - (Cy) _m -A ¹ -Pyr-R ⁶ Illb

wherein R ⁵ each alkyl with 1 to 12 carbon atoms, R ⁶ alkyl, alkoxy or alkanoyloxy each with 1 to 12 carbon atoms, m 0 or 1, pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl and A ¹ denotes Phe or Cy and Cy and Phe have the meanings indicated, and / or

at least one component selected from the compounds of the formulas IVa and IVb

R ⁷ -Dio-Phe-CN IVa

R ⁷ -A ° -Phe-NCS IVb

wherein R ⁷ each alkyl with 1 to 12 carbon atoms, A ° -Cy-, -Dio-, -Cy-Phe-, -Cy-Cy-, -Cy-Ph-CO-O- or -Cy-CH ₂ CH ₂ - means, and Dio and Phe have the meanings given.

2. Liquid crystal phase according to claim 1, characterized in that it contains at least one component selected from the compounds of the formulas Va and Vb

R ⁸ -Cy- (Phe) _n -CN Va

R ⁸ -Cy-Cy- (Phe) _n -CN Vb wherein R ⁸ each represents alkyl having 1 to 12 carbon atoms, n represents 1 or 2 and Cy and Phe each have the meanings given.

3. Liquid crystal phase according to claim 1 or 2, characterized in that it contains at least one component of the formula VI,

R ⁹ -Cy-A ¹ -ZA ² -R ¹⁰ VI

12 carbon atoms or CN, A ¹ and A ² each Cy or Phe and

Z means -CO-O-, -O-CO- or -CH ₂ CH ₂ -.

Use of liquid crystal phases according to one of Claims 1 to 3 for highly multiplexable electro-optical display elements.

Electro-optical display element for multiplex operation, characterized in that it contains a phase according to one of Claims 1 to 3.